Valves are commonly used in industry to restrict, divert, or blend flows of fluids. In the cryogenic industry, “top entry” valves are commonly used. These top entry valves present the advantage of eliminating flange connections (i.e. between the valve body and the bonnet), which represent a risk of leakage. Consequently, valves of this type eliminate the separate casing typically found in conventional valves, typically filled with mineral wool, thereby allowing for easy access to the valve internals in the case of leakage.
The absence of the separate casing filled with mineral wool implies that the valve and the connecting piping will need to be externally insulated, typically by being immersed with perlite inside the cryogenic cold box. This makes accessing the piping connected to the valve body virtually impossible, except by emptying the cold box of the perlite. This is a time consuming and expensive operation, resulting in extended plant outages.
In some cases, it can be desirable to access a stream internal to the cold box itself. For example, if the addition of a Helium-Neon enrichment column is envisioned. In the case where a top entry valve is in an appropriate location within the process cycle, the proposed invention would allow the top entry valve to be modified, in situ, to provide an exit and entry port for this process stream.